1. Technical Field
The invention relates to vehicle frames and in particular to frame hangers for mounting axle/suspension systems on the vehicle frame. More particularly, the present invention is directed to a hanger formed of aluminum which efficiently attaches to and forms a part of an aluminum vehicle frame, whereby the overall weight and cost of the frame is reduced as compared to aluminum frames which utilize steel hangers, and further whereby the aluminum hanger efficiently reacts loads emanating from the axle/suspension system during operation of the vehicle.
2. Background Art
A typical leading or trailing arm air-ride axle/suspension system is mounted on and depends from the frame of a vehicle by a pair of rigid frame hangers located adjacent to one of the ends of the axle/suspension system, and by a pair of flexible air springs disposed at the other end of the system. The conventional hanger is a fabricated welded steel box-like yoke structure that captures the bushing assembly end of a respective one of the pair of suspension arms or beams of the axle/suspension system, using a pivot pin or bolt. The steel hanger in turn is either welded or bolted to another component of the vehicle frame, depending on the material used for the frame. For vehicle frames formed of steel, the steel hanger typically is welded on, whereas for frames formed of aluminum, such as semi-trailer tanker trailers, the hanger must be bolted on because of the impracticality of welding together dissimilar metals.
Although steel hangers satisfactorily mount an axle/suspension system on steel or aluminum vehicle frames and successfully react loads emanating from the system during over-the-road operation of the vehicle, as noted immediately above, the steel hanger must be bolted rather than welded to an aluminum vehicle frame. In order to securely bolt the steel hanger to the aluminum frame, typically a pair of heavy mounting plates are disposed between the hanger and the frame to serve as an interface, which adds unwanted weight and cost to the vehicle. Such complicated bolt mounting also lessens the efficiency of the distribution of loads being transferred from the axle/suspension system, through the hanger, and into the other components of the vehicle frame. Such inefficiency often necessitates the use of add-on flanges, gussets and the like to the hanger and/or vehicle frame. Hangers which are welded directly to the vehicle frame without the use of intervening mounting plates and the like, can be much more efficient in transferring loads into the other components of the vehicle frame.
To avoid such problems associated with mounting steel hangers on otherwise aluminum frames, prior art aluminum hangers have been developed. However, such aluminum hangers have heretofore generally mimicked the design of steel hangers, with a resulting inability of the aluminum hanger to successfully react loads transferred to the hanger from the axle/suspension system, and especially lateral or side loads, without the use of additional flanges, gussets, and the like which add unwanted weight, complexity and cost to the hanger.
The present invention solves the problems of excessive weight and inefficient mounting of a steel hanger to an aluminum vehicle frame, as well as the problems associated with prior art aluminum hangers, through the use of a lightweight yet sturdy aluminum hanger construction which is easily mounted on an aluminum vehicle frame.
Objectives of the present invention include providing a hanger for aluminum vehicle frames which also is formed of aluminum, but which has a design sturdy enough to react loads emanating from the axle/suspension system, and further which mounts simply and directly to the other frame components for efficient transfer of such loads from the hanger into the other frame components.
These objectives and advantages are obtained by the aluminum frame hanger for axle/suspension systems of the present invention, the general nature of which may be stated as including an aluminum vehicle frame having a frame hanger for suspending a suspension assembly of an axle/suspension from the vehicle frame, the frame including a pair of transversely spaced longitudinally extending main members and a plurality of cross members extending between and interconnecting the main members, the axle/suspension system including a pair of transversely spaced suspension assemblies, each one of the pair of suspension assemblies including a longitudinally extending beam, the beams of the pair of suspension assemblies capturing a transversely extending axle having at least one wheel mounted on each end of the axle, the beams each including at one of its ends a bushing assembly for pivotally mounting the beam on the frame hanger, wherein the improvement comprises an integral frame hanger which substantially surrounds and laterally supports the bushing assembly, so that the hanger reacts lateral loads and other loads transferred from the axle/suspension system into the frame during operation of the vehicle, without requiring additional support structure on the hanger and on the main members and the cross members of the frame.